The present invention relates to a sheet glass attaching construction for attaching a sheet glass to a fixed member having a concave groove capable of receiving a peripheral edge of the sheet glass.
Conventionally, in a sheet glass attaching construction of this kind, as shown in FIG. 2, a sheet glass 2 is simply fitted into a fixed member 1A having a concave groove capable of receiving a peripheral edge of the sheet glass 2. And, after charging a filling material 7 such as of ceramic fiber into the concave groove 3a, a gap between the concave groove 3a and the peripheral edge is sealed with a sealant 6 or the like.
However, with the above-described sheet glass attaching construction, if a window glass is formed using this construction, the construction allows simple and easy installment by simply installing the fixed member, the sheet glass, the filling material and the sealant one after another. However, when the construction is subjected to a stress which pulls the sheet glass out of the concave groove, the sheet glass tends to be removed from the concave groove relatively easily. Normally, because of the rigidity of the sheet glass, such stress will not be applied to the concave groove of the sheet glass attaching construction. However, in the case of occurrence of a fire for instance, the sheet glass will be softened and readily deformed and the sheet glass may be bent due to its own weight. In that case, a pulling tension will be applied from the sheet glass to the concave groove. As a result, there sometimes develops a stress that pulls the sheet glass out of the groove.
In the occurrence of a fire, if such situation develops, the bending deformation or the like will cause the sheet glass to come off the fixed member, thus establishing communication between two spaces which were partitioned from each other by the sheet glass, so that the fire will spread to the adjacent space, causing a problem in the disaster prevention.
Incidentally, in order to solve such problem relating to the disaster prevention, an attempt has been made to prevent fire spreading by means of e.g. heat tempering. However, glasses having low softening points, such as soda-lime glass, have tended to receive low evaluation as a fire retarding door due to the above-described problem especially.
In view of the above-described drawbacks present in the prior art, an object of the present invention is to provide a sheet glass attaching construction which effectively restricts falling of the sheet glass off the fixed member even when the sheet glass becomes softened due to heat such as of a fire, and also to provide a glass window having a high fire retarding performance.
In order to achieve the above object, according to the characterizing features of a sheet glass attaching construction of the present invention, in a sheet glass attaching construction including a fixed member having a concave groove capable of receiving a peripheral edge of the sheet glass;
a pair of engaging portions are provided in the fixed member and the peripheral edge of the sheet glass respectively, the engaging portions coming into engagement with each other when the sheet glass is fitted into the concave groove, thereby to prevent the sheet glass from coming off the concave groove.
With the sheet glass attaching construction, of the invention even if a stress is developed to urge the sheet glass to come off the concave groove, the pair of engaging portions effectively resist this stress and prevents the sheet glass from coming off the concave groove. Therefore, even if the sheet glass becomes softened due to occurrence of a fire and deformed because of its self-weight, unless the stress applied to the sheet glass attaching construction due to the deformation exceeds the engagement force between the engaging portions, the force will not be sufficient to pull the sheet glass out of the concave groove. As a result, it is possible to reliably prevent the sheet glass from coming off the concave groove, thus prevent spread of the fire.
Further, at a side edge portion of the concave groove along a longitudinal direction thereof, there may be provided a projecting portion which projects in a direction to approach the sheet glass to be fitted into the concave groove, thus retaining the sheet glass fitted into the concave groove; and a fire-resistant adhesive having adhesiveness for glass may be charged within the concave groove.
As the fire-resistant adhesive having glass adhesive property referred to herein, so-called ceramic adhesive agents may be employed. For instance, an agent having a following composition given in the unit of wt. % may be employed; namely,
Incidentally, the fixed member may comprise a sheet glass holding member for securing the sheet glass to a window-glass fixing frame.
In the above, as the pair of engaging portions described above, it is conceivable to effect treatment on both an end portion of the sheet glass and the concave groove to provide them with the engaging portions. In particular, it is preferred that at a side edge portion of the concave groove along a longitudinal direction thereof, there be provided a projecting portion which projects in a direction to approach the sheet glass to be fitted into the concave groove, thus retaining the sheet glass fitted into the concave groove; and a fire-resistant adhesive having adhesiveness for glass be charged within the concave groove. With this, when the sheet glass is to be installed, the installment may be readily carried out by applying the fire-resistant adhesive to the fixed member and then fitting the sheet glass into the concave groove. Moreover, after the installment, the fire-resistant adhesive will be integrated with the glass. So that, when the sheet glass is urged to come off the concave groove, it engages with the projecting portion within the concave groove, whereby the projecting portion and the fire-resistant adhesive act as the pair of engaging portions. Therefore, a sheet glass attaching construction achieving the above-described function may be readily obtained advantageously.
Incidentally, in the above, the fire-resistant adhesive will be integrated with the end portion of the sheet glass upon installment of the sheet glass. Further, in the event of a fire, when the sheet glass is urged to come off the concave groove, it will engage with the projecting portion, thus preventing the sheet glass from coming off. In this respect, supposing a situation when even the end portion of the sheet glass begins to soften, the sheet glass and the fire-resistant adhesive will be even more integrated with each other, thus preventing the fluidized sheet glass from coming off the concave groove.
Further, a glass window according to the present invention for achieving the above-noted object is characterized in that the above-described sheet glass attaching construction is employed at least at an upper end portion of the glass window.